Journal of Food Science · 1978 · 27 citations · 6 references
Natural SciencesMaterials EngineeringMaterials ScienceMechanical Behavior Of MaterialsPolymer ChemistryPolymer EngineeringFracture MechanicsGelsHydrogelsMechanical CharacterizationPectin ChemistryStress RelaxationCompositional Data AnalysisGel ElasticityGel MechanicsMechanical Properties Of GelsMolecular Weight DeterminationPectin CharacterizationPectin Molecular WeightRelaxation Time Measurements
ABSTRACT Low‐ester pectin gels were prepared by acid and a combination of acid and ammonium hydroxide demethylation. The chemical compositional data such as percent esterification, acid amide, free carboxyl, galacturonic acid and apparent molecular weight of the gels were determined. The maximum stress, modulus of elasticity and relaxation time prior to fracture of the low ester pectin gels were evaluated using a universal testing machine. Significant correlations were obtained between (a) relaxation time during fracture propagation and percent esterification; (b) maximum stress and molecular weight; and (c) maximum stress and percent acid amide groups. It was also found that percent acid amide groups in the pectin contributed to the strength of the gels over and above the effect of decreasing percent free carboxyl groups.
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